Rainbow Electronics DS1302 - Manual

E Copyright 1995 by Dallas Semiconductor Corporation.
All Rights Reserved. For important information regarding
patents and other intellectual property rights, please refer to
Dallas Semiconductor data books.
DS1302
Trickle Charge Timekeeping Chip
DS1302
041697 1/12
FEATURES
•
Real time clock counts seconds, minutes, hours, date
of the month, month, day of the week, and year with
leap year compensation valid up to 2100
•
31 x 8 RAM for scratchpad data storage
•
Serial I/O for minimum pin count
•
2.5–5.5 volt full operation
– Optional 2.0–5.5 volt full operation also available
•
Uses less than 300 nA at 2.5 volts
•
Single–byte or multiple–byte (burst mode) data trans-
fer for read or write of clock or RAM data
•
8–pin DIP or optional 8–pin SOIC’s for surface mount
•
Simple 3–wire interface
•
TTL–compatible (V
CC
= 5V)
•
Optional industrial temperature range –40 ° C to +85 ° C
•
DS1202 compatible
•
Added features over DS1202
– Optional trickle charge capability to V
CC1
– Dual power supply pins for primary and backup
power supplies
– Backup power supply pin can be used for battery
or super cap input
– Additional scratchpad memory (7 bytes)
PIN ASSIGNMENT
DS1302
V CC1
SCLK
I/O
RST
V CC2
X1
X2
GND
1
2
3
4
8
7
6
5
V CC1
SCLK
I/O
RST
V CC2
X1
X2
GND
1
2
3
4 8
7
6
5
DS1302S 8–PIN SOIC (200 MIL)
8–PIN DIP (300 MIL)
DS1302Z 8–PIN SOIC (150 MIL)
PIN DESCRIPTION
X1, X2 – 32.768 kHz Crystal Pins
GND – Ground
RST – Reset
I/O – Data Input/Output
SCLK – Serial Clock
V
CC1
, V
CC2
– Power Supply Pins
ORDERING INFORMATION
PART # DESCRIPTION
DS1302 Serial Timekeeping Chip; 8–pin DIP
DS1302S Serial Timekeeping Chip;
8–pin SOIC (200 mil)
DS1302Z Serial Timekeeping Chip;
8–pin SOIC (150 mil)
DESCRIPTION
The DS1302 Trickle Charge Timekeeping Chip contains
a real time clock/calendar and 31 bytes of static RAM. It
communicates with a microprocessor via a simple serial
interface. The real time clock/calendar provides
seconds, minutes, hours, day, date, month, and year
information. The end of the month date is automatically
adjusted for months with less than 31 days, including
corrections for leap year. The clock operates in either
the 24–hour or 12–hour format with an AM/PM indicator. Interfacing the DS1302 with a microprocessor is simpli-
fied by using synchronous serial communication. Only
three wires are required to communicate with the clock/
RAM: (1) RST (Reset), (2) I/O (Data line), and (3) SCLK
(Serial clock). Data can be transferred to and from the
clock/RAM one byte at a time or in a burst of up to 31
bytes. The DS1302 is designed to operate on very low
power and retain data and clock information on less
than 1 microwatt.